If your desired payment method is not displayed under Payment methods you can add it by clicking on the drop down box labelled Select entry.
Once selected click the Plus icon to add it to the list.

Now we have the Payment Method of choice added you will need to enter a few details before activating it, to do this click on the Complete it option as shown below.

On the next page is a list of instructions regarding signing up to and using a HSBC as a payment method, if you have not already done so I recommend following all of these steps.

Once you have done this fill in the Data for HSBC configuration, you will have this information from following the steps that I recommended.
Finally select your transaction type, Operational mode and the Icon you would like to show on your Ecommerce Shop.